In the era when mobile phones were rapidly getting smaller and thinner (this was referred to as keihakutansho, which means light, thin, short, and small), it goes without saying that their electronic components also had to get smaller and shorter. We thought that if things were going to continue getting so small, we should try developing inductors that were not just one size smaller, but two or more sizes smaller. Thinking such a thing is easy, but that thought ended up being the start of a tortuous product development process.
At the time, a decrease in winding inductor size to 2,520 mm was demanded, and, of course we expected that each of our rival companies would be working on new products of this size. However, we decided to try to go all the way down to 2,016 mm and create the world's smallest winding power inductor. We were also particular about the component height. At the time, 1.5 mm was the norm, and future heights of 1.2 mm were being demanded, but in this area as well, we wanted to go lower than 1 mm and aim for new product heights of 0.95 mm max. and 0.7 mm max., which would be the shortest in the world and would have a big impact on the industry.
This was the start of a development process that epitomized the phrase, "easier said than done." After we had handled each of the problems that we were confronted with one by one, the final obstacle in our path was ultra-compact electrode design. The development took place around the time when lead-free soldering started, so it was also essential to design components that were soldered without lead. We ended up having to create a low-cost design using the new electrode forming method introduced in "Anecdote of inductor development [No. 5] Trends in LQH solder mounting technology" and, at the same time, having to deal with the issue of removing lead soldering from our designs.
On a weekend, I was with my son at the park, but all I could think about was electrode design. I kept thinking about how to solve the problem and trying to come up with new ideas. I was hardly paying any attention to my son. Of course, he realized this and said, "you're boring, dad!" as he jumped from a swing and ran to go play on another piece of playground equipment. But I just stood still and kept thinking. In front of my eyes, the swing was swaying back and forth over a puddle of water at my feet. That's when it hit me. In an instant, I visualized the moving swing seat, the puddle, and my own eyes as part of an electrode manufacturing device. "Of course! You just have to move it!" In less than a second, I had hit upon a precision electrode formation technology utilizing a swing principle. What's more, this method wouldn't use any soldering, let alone lead soldering. I still remember that moment vividly.
Ah! Of course, after that, I rushed to find where my son had gone off to.
Written by: T.M., Ceramic Production Dept. 4, EMI Division